trace_event.h tracking issue #30

This is a tracking issue for trace_event.h integration. If I've missed anything, please add it.

• Overview from @ofrobots: Tracing WG Meeting 2015-09-25 #21 (comment)
• In-depth design rationale from @natduca: tracing working group node#671 (comment)
• V8 change list: https://codereview.chromium.org/988893003/
• Chromium parts: trace_log.h, trace_log.cc, trace_buffer.h, trace_buffer.cc

TODO:

• Add trace_event.h files to node, or wait for V8 release with it?
• Create node equivalent to trace_log and trace_buffer in Chromium
  • Need a thread to consume trace data
  • Create JS interface to allow custom storage methods. (Use C++ Streams?)
• Use TRACE_EVENT_BEGIN0, TRACE_EVENT_END0, TRACE_EVENT_ASYNC_BEGIN0, TRACE_EVENT_ASYNC_END0 macros in node codebase (AsyncWrap might be a good place to start)